Try not to get to overwhelmed by it. If you start working on it for even 2 hours a week now you'll have it finished with time to spare! Break it up into sections so it doesn't seem so big & daunting.
Being told by previous yr 12's not to leave the PIP until the last minute, then leaving it till the last minute, then telling the upcoming yr 12 not to leave it until last minute seems to be a bit of a tradition. So on that note- DON'T LEAVE IT UNTIL LAST MINUTE.
!!good luck!!